Re: OP1 and CW filter gain difference?

Posted by Stewart Baker on Apr 08, 2005; 5:32pm
URL: http://elecraft.85.s1.nabble.com/OP1-and-CW-filter-gain-difference-tp376780p376784.html

Marteinn,

The CW filter has a greater signal loss than the OP1 filter mainly because of
it's varicap variable bandwidth design. My K2 has about a 6dB loss relative to
the OP1. Your CW filter loss of 10dB may be a bit high. I would check the
varicap lead orientation.

73
Stewart G3RXQ

On Fri, 8 Apr 2005 15:49:53 +0000, Marteinn Sverrisson wrote:

> Hi All
>
> I was measuring the gain difference of the OP1 x-tal filter and the
> CW filter on my K2.
>
> It seems that the OP1 filter has +10dB more gain than the CW filter
> I have the 2.5kHz OP1 filter mod and the stock CW filter on 2.4kHz.
> Measurements are done on 7 MHz band on LSB.
>
> I did the measurements with AGC off, using noise gen and audio
> spectrum analyzer.
>
> Is this normal?
>
> Should I look for some bad X-tals or varicaps in the CW filter?
>
> 73 de TF3MA
>
> PS. same results if I unmodule the KSB2, the gain is still low.

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